Clays and Clay Minerals

, Volume 3, Issue 1, pp 103–116 | Cite as

DTA of Kaolinite and Montmorillonite Under Water Vapor Pressures up to Six Atmospheres

  • Robert L. Stone
  • Richards A. Rowland


Thermograms of kaolinite and montmorillonite were obtained at water-vapor pressures varying from approximately 0.0001 to 4,500 mm. of Hg with a variable pressure, dynamic gas, differential thermal analysis apparatus. The beginning of the kaolinite endotherm is shifted to a higher temperature with increasing water-vapor pressure. The sharp kaolinite exotherm is shifted to a lower temperature until at six atmospheres water-vapor pressure it makes a small broad peak at approximately 900° C. The dehydroxylation endotherm of montmorillonite is almost unaffected. The 900° C endotherm and the recrystallization exotherm are shifted to a lower temperature with increasing water-vapor pressure. The temperatures of the start of the endothermic peaks associated with exchange cations are shifted upward by increased gas (N2) pressure.


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Copyright information

© The Clay Minerals Society 1954

Authors and Affiliations

  • Robert L. Stone
    • 1
  • Richards A. Rowland
    • 2
  1. 1.University of TexasUSA
  2. 2.Shell Development Co.USA

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